Some prior art conveyor chains are comprised of rows of molded plastic chain modules pivotally joined together by chain pins. Each module of such chains has a plurality of spaced link ends which intermesh with the complementary link ends projecting from a module in an adjacent row. Further, each link end has therein a bore which is coaxially aligned with the bores of other link ends to house the chain pin. In some arrangements, the chain pin projects from each edge or side of the conveyor chain and is provided with a head on one end of the chain pin to restrict axial movement of the chain pin. The head can be preformed but, in most cases, the head is formed by heat and pressure after the chain pin has been placed in position in the module. The head also projects from the side of the conveyor and can catch or drag on adjacent structures thus requiring additional lateral clearance between the conveyor and the conveyor guide or between adjacent conveyor chains. To remove the chain pin from an assembled chain, the head on one end of the chain pin has to be cut off. Once the head is severed, the chain pin becomes unusable because its length is too short to form a new head.
Other prior art conveyor chains include plugs housed in the opposite ends of the link end bores to restrict axial movement of the chain pins. The plugs of such chains are normally small parts that can be lost or dropped on the floor of a production facility when they are inserted or removed from the modules. In some prior art constructions, these plugs have a tendency to be dislodged or pop out of the module when the conveyor chain is in use. Without the plug restricting axial movement of chain pin, the chain pins can become dislodged from their proper position and cause a disruption in the conveyor assembly.